40k has got out of hand with min/max gameplay, you have to go for all the best options in your army and allies to even have anything like a fair game, and some of the players and lists are just not worth even trying against.
Officially in the rules, you measure from models. A lot of places just can't get there head out of bases, and insist on measuring to bases. I'd change the rule to say the base is part of the model. Stuff that massively overhangs the base makes sense it can reach further than it's base, but you also don't want a giant base for a tiny model. I get that stacking is frowned upon, I wouldn't want someone to put their models on top of mine, it risks chipping and scratching, or rubbing off flock.
I have put all my Stormcast on 40mm squares, partly because I thought someone might come up with rules for 8th/9th, but also just to troll people who care too much about what base shape and size should be used. As it makes so little difference. I think if you care that much, all that really means is you're trying to either get or deny an extra attack or two for that microscopic advantage, and that feels to me a bit unsporting
As for second turn, I assume that means they have no roll-off for turn order each round, and it's always player1-player2. It's a real headache to get used to but it's very much a signature characteristic of the game to take into account that your opponent or yourself might get a double-turn. In some games it can kill off a game, in others it means a complete swing around. It's one of those vagaries that makes a game different, and unpredictable. The last thing I want to see is the same game with the same result every time.