I can answer the first part. A henna gloss is simply mixing up henna with warm water(or another liquid), waiting for color release and then instead of applying to your hair as you would for a full henna treatment, you add condtioner. Some use half henna and half conditioner. Make sure it is a moisturizing conditioner though. I am not at all familiar with te henna gloss conditioner or the gloss bar you mentioned. I think the question that needs to be asked is if you plan on using chemical dyes in the future. The issue with any chemical dye and the result you will get from henna varies. I'll come bck to that later unless one of the ladies here answers first. Henna and chemical dyes can be complicated. What are the names of the henna products you plan on using? I can't see any mentions on my IPhone. PM me if it is a must see. Allons y