Questions for first-timers

[JKLJKLJKL]

SWIM and two of his friends are planning to try H in the nearish future. Now they are trying to do this as sensibly as possible, they will be buying a gram from a reliable source - someone they have bought E from before without a problem. They are going to have a house to themselves for a week and spend either the first night or the first couple of the nights doing it.

SWIM and his friends have a few questions.
1. what do SWIY suggest as the best way to do it for a first time, none of them what to do it injecting because SWIM and his friends are a bit apprehensive about this, whereas smoking and snorting they are fine with. But which will be better for him? - taking into account, ease etc, and what dosages should be used.
2. Considering this is first time on H, how much should be used to start with, SWIM has read 10-20mg if smoking, say each of SWIM and his friends do that, how long after will it be till they will feel the need to "top up", or will they at all? and what is a safe number of times SWIM can top up.
SWIM and his friends are used to taking Pills, Coke and MDMA and have relative tolerances to those but never touched any opiates.
3. SWIM wonders what the comedowns are like, they have the house to themselves for a few days afterwards so that they dont have to face people and life in gneral. But what are the comedowns like? Compare say to an MDMA comedown...?
4.Finally SWIM wants to know if anything combats comedowns. SWIM read that smoking crack helps somewhere, but as he hasnt done this before he wonders whether trying that for first time as well would eb worth it. would there be much problem with SWIM using a few pills the night after H to help with the comedown or would it be best just not to touch anything till SWIM feels better?

SWIM apprieciates all help given, and wants to make this first time enjoyable but also as safe as he can.