Well, for me, it's not just a matter of which slot, but also about taking a bonus or not, i.m.o.
There's this other thread i spotted, about if bonuses are favorable for players or rather the casino's and i was going to reply there, but instead ill do it here, since it applies to both
I am one of those players that almost always deposits the minimum, or close to it. Reason for that mainly being, that i count each deposit as lost before starting, and as such i want to lose as little as possible. So mostly i deposit 10,-
In
Unibet and Maria, i can deposit a minimum of 15,- with Neteller, my preferred method, or 5,- with direct-banking.
In
32Red i can deposit 10,- with each method, in MrGreen i can deposit 5,- with Neteller, 10,- with D-bank, and in Redbet a minimum of 20,-..
My other fav's (3 Dice, CasinoLuck/Nxt, V&J, IGame etc.) are all 10,- minimum, and most of them allow taking a bonus with that minimum deposit amount.
Most people think a bonus is crappy, unless its a high percentage with low playthrough, but i concur, that especially when depositing minimal amounts, any normal bonus can be a very good idea. Again i say the prerequisite is thinking of the deposit as a loss, and ipso facto the bonus is only to get a few more spins in.
This also gives me purpose, and the goal is to prevent the inevitable loss, by playing either conservatively, like you said on slots like Doa, Reel Steal, Break the Bank Again on 0.09 ct, Piggy Riches or Fruit Shop or other 15 liners with a 0.15 ct minimum, or Attraction, Starburst or for instance the new Quickspin slot Second Strike, on 0.10 ct, and then see if you can double the balance, or even better: When that happens, and i must say it often does, i can pick whatever slot i feel like, and play the next level of slots with 0.20 or 0.25 ct minimum, and try and repeat the same, so either double or better, or sometimes i will just play till the feature comes, then move on.
Of course there are no real rules, sometimes i just stick to a slot, regardless of what happens, because i feel it's hot, or whatever.
I've noticed that when i play like this, i.e. minimal depo with bonus, i generally really make playthrough more easily then when i would take 100% match up's on deposits of 25,- or more.
There's also the option to leave the bonus out of the picture, and the low min bets method still works well.
Also just for the heck of it, mostly when new games are launched, make a min depo, to check them out, regardless of the min bet size, and just go for it. Sometimes this works too, but i can with certainty say, that the minimum depo + bet size has more chances
Important factor is of course which casino you pick too: i only play at places i mentioned, where i know this playstyle isn't punishable by the T&C's, but i know if you pick unaccredited places, or a lot of the white label-type newer places, you may be bonus banned soon, or even banned all together.
Another thing i try on small balances, is Video Poker on minimum bet's, when in RTG that, can be 0.01 cent, but mostly it's 0.10 cent or up, but due to the nature of VP, you can expect some playtime, or try your luck with the gamble feature (in this case of course without a bonus, as this is sometimes considered a no-no) until you double up the balance, then switch to slots.
That's my 2 cents on the matter