Hi There LOHI34
4.5m is a bit long but it can be done. Just remember to flush a bit longer to make sure that all the waist goes into the tank and does not lay in your pipe leading to the tank. If you have the money
to spend then look at a vacume system but once again, keep your systems as simple as possible, less to go wrong.
To mount your tank in a high position is a "good" thing. it just means that you can drain your tank through gravity instead of a pump.
What pumps to use? If you are installing a electrical
toilet then the pump on the unit will able to do the work, if installing a manual toilet, cancel your gym contract
, you will get a nice work out.
Do not forget your deck
evacuation piont, tank breather and siphon loops.
Good luck with restoration